1. Field of the Invention
The present invention relates to a through wiring substrate that has a through-wire which penetrates the interior of a substrate (interposer substrate with through-hole interconnection) and a manufacturing method thereof.
2. Description of the Related Art
Conventionally, a method of providing a through-wire that penetrates the interior of a substrate (through-hole interconnection) is used as a method of electrically connecting a first device, mounted on a first face which is one face of the substrate, to a second device, mounted on a second face which is another face of the substrate. The substrate with the through-wire is often called interposer.
As an example of a through wiring substrate (interposer), Patent Document 1 (Japanese Unexamined Patent Application, First Publication No. 2006-303360) describes a through wiring substrate including a through-wire made by filling an electrically-conductive substance into a microscopic hole having a section that extends in a direction different from the thickness direction of the base material.
An example of this is a through wiring substrate such as that shown in FIG. 8. This through wiring substrate 100 includes a through-wire 101, which is formed by providing a through-hole 104 that links one face of a substrate 102 made from silica glass or the like with one side face of the substrate 102, and filling an electrically-conductive substance 106 into the through-hole 104. The through-wire 101 has a substantially right-angled bend part, and a linear part 101b extending in the thickness direction of the substrate and a linear part 101a extending in a direction (long direction) that is different from the thickness direction of the substrate are connected at the substantially right-angled bend part.
When a through-wire provided in a conventional through wiring substrate has a substantially right-angled bend part, there is a problem that current concentrates in the inner peripheral part of the bend part, resulting in increased transmission loss of electrical signals, and in particular of high-frequency signals, via the through-wire. There is also a problem that an electrically-conductive substance filled by a method such as supercritical film formation method peels away from the through-hole at the sharp end parts of the bend parts, resulting in poor conductivity.